Device for mapping a sensor&#39;s baseline coordinate reference frames to anatomical landmarks

ABSTRACT

A coordinate locating device comprising a support structure removably connectable to a wearable sensor device being worn by an individual. The support structure comprising a planar surface. The device includes a plurality of different fiducial marker components connected to the planar surface. The plurality of different fiducial marker components includes a set of fiducial markers connected to the planar surface in a non-collinear configuration relative to each other to define a three-dimensional (3D) space of pixels in an image. The plurality of different fiducial marker components includes a distance calibration fiducial marker connected to the planar surface and being configured to define a distance calibration length of pixels in the image, the distance calibration fiducial marker being perpendicular to the planar surface and defining a calibration length to locate a point of origin of motion sensing by the wearable sensor device. A system and method are also provided.

FIELD

The present technology is generally related to devices for mapping abaseline coordinate reference frame of one or more sensors to one ormore anatomical landmarks via ionizing radiation imaging.

BACKGROUND

Motion sensors attached to a patient can be used to assess many aspectsof gait and posture. However, the motion sensor data can be difficult toassociate with a suspected pain generator when the relationship betweenthe sensor data and the patient's boney anatomy structures is unknown.Currently, the position of attached motion sensors with respect tomusculoskeletal anatomy may be estimated using anthropometricrelationships. However, estimating the position of motion sensorsrelative to the musculoskeletal using anthropometric relationships isimprecise.

Motion data is easy to collect and analyze, but it is collected from adevice that sits outside of the subject's body. Motion data may provideinsights about a person' gait, posture, balance, etc. However, motiondata alone does not indicate which specific anatomical part of the bodyis actually moving as the motion data is collected.

SUMMARY

The techniques of this disclosure generally relate to a system, methodand device that are configured to map a coordinate reference frame ofone or more sensors embedded in a wearable sensor device to anatomicallandmarks. The anatomic landmarks may include bones, joints, and organssuch as without limitation a heart. In some embodiments, the system,method and devices correlates a suspected pain generator with motionsensed data.

In one aspect, the disclosure provides a coordinate locating deviceincluding a support structure removably connectable to a wearable sensordevice being worn by an individual. The support structure includes aplanar surface. The device includes a plurality of different fiducialmarker components connected to the planar surface. The plurality ofdifferent fiducial marker components includes a set of fiducial markersconnected to the planar surface in a non-collinear configurationrelative to each other to define a three-dimensional (3D) space ofpixels in an image. The plurality of different fiducial markercomponents includes a distance calibration fiducial marker connected tothe planar surface and being configured to define a distance calibrationlength of pixels in the image. The distance calibration fiducial markeris perpendicular to the planar surface and provides a calibration tolocate a point of origin of motion sensing by the wearable sensordevice.

In another aspect, the disclosure includes a system comprising awearable sensor device that includes an inertial measurement unit (IMU)and an ionizing radiation sensor. The ionizing radiation sensor isconfigured to, in response to sensing ionizing radiation, trigger abaseline timestamp to synchronize IMU data from the inertial measurementunit. The system includes a coordinate locating device that isconfigured to be removably attached to the wearable sensor device. Thecoordinate locating device includes a plurality of different fiducialmarker components that is radiopaque to the ionizing radiation in acaptured image.

In yet another aspect, the disclosure a method that includes sensing, bya wearable sensor device including an inertial measurement unit (IMU),inertial measurement data associated with an anatomical position of aboney anatomical structure. The method includes sensing, by an ionizingradiation sensor of the wearable sensor device, ionizing radiation totrigger a baseline timestamp to synchronize the inertial measurementdata from the inertial measurement unit with an internal clock. Themethod includes imaging, using the ionizing radiation, a coordinatelocating device attached to the wearable sensor device and including aplurality of different fiducial marker components being radiopaque tothe ionizing radiation in a captured image.

The details of one or more aspects of the disclosure are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the techniques described in this disclosurewill be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded view of an embodiment of a motion sensor system.

FIG. 2A is a side view of the motion sensor system of FIG. 1 with anembodiment of a housing of a wearable sensor device shown thecross-section, the gravity indicator shown in phantom and the coordinatelocating device installed.

FIG. 2B is a side view of the motion sensor system of FIG. 2A with adistance calibration phantom and the point of sensing origin indicated.

FIG. 2C is a top view of the motion sensor system of FIG. 1 .

FIG. 3 is a side view of an embodiment of the wearable sensor devicewith the housing shown in cross-section.

FIG. 4 is a diagram of an example of the motion sensor system attachedto a patient being imaged, the housing of the wearable sensor deviceshown in cross-section.

FIG. 5 is a block diagram of example electrical components of thewearable sensor device.

FIG. 6A is a diagram of axes of the human anatomy.

FIG. 6B is a diagram of the planes of the human anatomy.

FIG. 7 is a flowchart of an embodiment method for generating a map of asensor's baseline coordinate reference frame.

FIG. 8 is a flowchart of an embodiment method for generating a map of amotion sensor coordinate reference frame.

FIG. 9A is a flowchart of an embodiment method for analyzing the map ofthe sensor's baseline coordinate reference frame.

FIG. 9B is a diagram of an example sagittal plane offset.

FIG. 10 is a flow chart of an embodiment method for identifying fiducialmarker components of a coordinate locating device and the orientationrelative to the X-ray plane to locate the point of sensing origin of aninertial measurement unit (IMU).

FIG. 11 is a flowchart of an embodiment method for determining anorientation of a set of non-collinear fiducial markers relative to theX-ray plane to generate a three-dimensional (3D) space pixel metric fora sensor's baseline coordinate reference frame.

FIG. 12 is a flowchart of an embodiment method for identifying thedistance calibration phantom pixel metric for the sensor's baselinecoordinate reference frame.

FIG. 13 depicts an example of internal hardware that may be included inany of the electronic components of an electronic device.

DETAILED DESCRIPTION

The present invention may be understood more readily by reference to thefollowing detailed description of the embodiments taken in connectionwith the accompanying drawing figures, which form a part of thisdisclosure. It is to be understood that this application is not limitedto the specific devices, methods, conditions or parameters describedand/or shown herein, and that the terminology used herein is for thepurpose of describing particular embodiments by way of example only andis not intended to be limiting.

In some embodiments, as used in the specification and including theappended claims, the singular forms “a,” “an,” and “the” include theplural, and reference to a particular numerical value includes at leastthat particular value, unless the context clearly dictates otherwise.Ranges may be expressed herein as from “about” or “approximately” oneparticular value and/or to “about” or “approximately” another particularvalue. When such a range is expressed, another embodiment includes fromthe one particular value and/or to the other particular value.Similarly, when values are expressed as approximations, by use of theantecedent “about,” it will be understood that the particular valueforms another embodiment. It is also understood that all spatialreferences, such as, for example, horizontal, vertical, top, upper,lower, bottom, left and right, are for illustrative purposes only andcan be varied within the scope of the disclosure. For example, thereferences “upper” and “lower” are relative and used only in the contextto the other. Generally, similar spatial references of different aspectsor components indicate similar spatial orientation and/or positioning,i.e., that each “first end” is situated on or directed towards the sameend of the device. Further, the use of various spatial terminologyherein should not be interpreted to limit the various locationtechniques or orientations for identifying objects or machines.

An “electronic device” or a “computing device” refers to a device orsystem that includes a processor and memory. Each device may have itsown processor and/or memory, or the processor and/or memory may beshared with other devices as in a virtual machine or containerarrangement. The memory will contain or receive programming instructionsthat, when executed by the processor, cause the electronic device toperform one or more operations according to the programminginstructions. Examples of electronic devices include personal computers,servers, mainframes, virtual machines, containers, cameras, tabletcomputers, laptop computers, media players and the like. Electronicdevices also may include appliances and other devices that cancommunicate in an Internet-of-things arrangement. In a client-serverarrangement, the client device and the server are electronic devices, inwhich the server contains instructions and/or data that the clientdevice accesses via one or more communications links in one or morecommunications networks. In a virtual machine arrangement, a server maybe an electronic device, and each virtual machine or container also maybe considered an electronic device. In the discussion above, a clientdevice, server device, virtual machine or container may be referred tosimply as a “device” for brevity. Additional elements that may beincluded in electronic devices are discussed, for example, in thecontext of FIG. 5 .

The terms “processor” and “processing device” refer to a hardwarecomponent of an electronic device that is configured to executeprogramming instructions. Except where specifically stated otherwise,the singular terms “processor” and “processing device” are intended toinclude both single-processing device embodiments and embodiments inwhich multiple processing devices together or collectively perform aprocess.

The terms “memory,” “memory device,” “data store,” “data storagefacility” and the like each refer to a tangible and non-transitorydevice on which computer-readable data, programming instructions or bothare stored. Except where specifically stated otherwise, the terms“memory,” “memory device,” “data store,” “data storage facility” and thelike are intended to include single device embodiments, embodiments inwhich multiple memory devices together or collectively store a set ofdata or instructions, as well as individual sectors within such devices.

In this document, the terms “communication link” and “communicationpath” mean a wired or wireless path via which a first device sendscommunication signals to and/or receives communication signals from oneor more other devices. Devices are “communicatively connected” if thedevices are able to send and/or receive data via a communication link.“Electronic communication” refers to the transmission of data via one ormore signals between two or more electronic devices, whether through awired or wireless network, and whether directly or indirectly via one ormore intermediary devices.

In this document, the term “imaging device” or “imaging machine” refersgenerally to one or more hardware sensors that are configured to acquireimages, such as radiographic images. An imaging device may captureimages, and optionally may be used for other imagery-relatedapplications. For example, an imaging device can be an image camera,X-ray machine, computed tomography (CT) scan machine or other ionizingradiation imaging devices. The imaging device may be part of an imagecapturing system that includes other hardware and/or softwarecomponents. For example, an imaging device can be mounted on anaccessory or support structure. The imaging device can also be mountedto a wall, ceiling or other support. The imaging device may include atransceiver that can send captured digital images to, and receivecommands from, other components of the system.

The disclosure provides a coordinate locating device having differentradiographic fiducial marker components positioned a certain distancefrom one or more sensors located inside of a wearable motion sensordevice being worn by a patient to generate a sensor's baselinecoordinate reference frame when imaged. The sensor device may beconfigured to allow a patient to be imaged with ionizing radiation, forexample, while wearing the sensor device. The resultant images can beused to determine the distance from the motion sensor of the sensordevice to relevant boney anatomy structures.

FIG. 1 is an exploded view of an embodiment of a motion sensor system100. The motion sensor system 100 may include a wearable sensor device105 and a coordinate locating device 135 removably coupled to thewearable sensor device 105. The wearable sensor device 105 may include ahousing 110 configured to be attached to a wearer, such as a wearer'strunk or back.

The system 100 of FIG. 1 will be described also in relation to FIGS.2A-2C and 3-4 . FIG. 2A is a side view of an embodiment of the motionsensor system 100 of FIG. 1 with the housing 110 of a wearable sensordevice 105 shown in cross-section, a gravity indicator, denoted by thereference numeral 150, shown in phantom and the coordinate locatingdevice 135 installed. FIG. 2B is a side view of an embodiment of themotion sensor system 100 of FIG. 2A with a distance calibration phantomand the point of sensing origin (e.g., point denoted by 0, 0, 0)indicated. FIG. 2C is a top view of an embodiment of the motion sensorsystem of FIG. 1 . FIG. 3 is a side view of an embodiment of thewearable sensor device 105 with the housing shown in cross-section. FIG.4 is a diagram of an embodiment of the system 100 attached to a patientbeing imaged by imaging machine 410, the housing of the wearable sensordevice 105 shown in cross-section. The point of sensing origin may belocated to define the point of motion sensing that corresponds to acenter of sensing by the IMU 132. The wearable sensor device 105 may notbe movable (i.e., remains stationary) with respect to the boney anatomylandmark after the imaging measurements are taken.

The coordinate locating device 135 may include a support structure 136removably connectable to a wearable sensor device 105, the supportstructure 136 may include a planar surface 137. The coordinate locatingdevice 135 may include different fiducial marker components 140, 150 and160 that may be connected to the planar surface 137 of the supportstructure 136. By way of non-limiting example, a first fiducial markercomponent may include a set of fiducial markers 141, 142, 143 connectedto the planar surface 137 in a non-collinear configuration relative toeach other to define or locate a three-dimensional (3D) space of pixelsin an image. The set of fiducial markers may include three fiducialmarkers positioned at certain distances relative to each other and atcertain angles to define a 3D space of pixels in an image. Additionaland/or alternate number of fiducial markers may be used within the scopeof this disclosure.

Each different fiducial marker component 140, 150 and 160 providesdifferent coordinate location parameters. For example, the firstfiducial marker component 140 may provide a three-dimensional locationand orientation parameter. A second fiducial marker component mayprovide the direction of the gravity vector. A third fiducial markercomponent 160 may locate a point of sensing origin of the motion sensorof the wearable sensor device 105.

In the illustrations, a set of three markers are shown including a firstmaker 141, a second marker 142 and a third marker 143. There are threearms, one for each marker. Some portion of the markers 141, 142 and 143may be arranged in 3D space via the known configuration of the markersupport structure 145 so that when analyzing the images using imageprocessing, the computing system knows the orientation and location ofthe device 105 from a two-dimensional (2D) image. The marker supportstructure 145 may include marker support arms 147 with each armsupporting a respective one fiducial marker of the marker set (i.e.,first fiducial marker component 140). The fiducial markers 141, 142 and143 are is shown as radiopaque ball-shaped elements. However, othergeometric shapes, such as a three-dimensional shaped square, triangle,rectangle, or other shape, may be used.

The third fiducial marker component 160 may include a distance locatorfiducial marker, denoted by the reference numeral 160, connected to theplanar surface 137 that may be configured to define a distancecalibration phantom length D1 of pixels in an image. The distancelocation fiducial marker 160 may be perpendicular to the planar surface137. The distance locator fiducial marker 160 may include a stem 162having a stem length. The stem may include a first end connected to theplanar surface 137. The distance locator fiducial marker 160 may includea radiopaque marker connected to a second end of the stem 162, theradiopaque fiducial marker 160 has at least one dimension. For example,the radiopaque fiducial marker 160 may have a geometric shape with adimension that extends the length of the step. The distance locatorfiducial marker 160 may include a notch 164 formed in the stem 162 wherethe distance calibration phantom length D1 is measured from a locationassociated with the notch 164 to a location of the radiopaque fiducialmarker 160. In the illustration, the location is the furthest end of theradiopaque marker.

The fiducial marker 160 is shown as a radiopaque ball-shaped element.However, other geometric shapes, such as a three-dimensional shapedsquare, triangle, rectangle, or other shape, may be used.

The second fiducial marker component 150 may include at least onegravity direction fiducial marker 154, shown in phantom. The at leastone gravity direction fiducial marker 154 is responsive to a force ofgravity such that the force of gravity moves the at least one gravitydirection fiducial marker 154 to indicate a direction of gravity vectorat an instantiation of imaging at which the image is captured. Thesupport structure 136 may further include a chamber 152, show inphantom, mounted to the planar surface 137. The at least one gravitydirection fiducial marker 154 may include a plurality of looseradiopaque balls configured to move within the chamber 152 in responseto the force of gravity. By way of non-limiting example, the chamber 152is formed in a housing 156 where the housing 156 is mounted to theplanar surface 137. In another scenario, the chamber 152 may be fluidfilled with at least one gravity direction fiducial marker being afloatation element. The gravity direction fiducial marker 154 iscaptured in an image to show the direction of the gravity vector whenthe patient is at rest, such as during imaging of the patient.

The different fiducial marker components may be fabricated from ofmetal, plastic or other composite material that is radiopaque inresponse to ionizing radiation. In some embodiments, each fiducialmarker of a different function may have a different level ofradiopacity, in response to the ionizing radiation of the imagingmachine 410 so that the different functional elements of the markercomponents can be distinguished. In other scenarios, the fiducial makerof a different function may have a different geometric shape fordistinguishing the different markers. Some fiducial marker's may bepassive markers while some are active markers (i.e., light emittingdiode).

The different coordinate locating functions by the coordinate locatingdevice will be described in more detail in relation to FIGS. 9A-9B and10-12 . The support structure 136 may include side walls 138A and 138Bthat may be parallel to each other and perpendicular to the planarsurface 137. The distance between the first and second side walls 138Aand 138B allows the housing 110 of the wearable sensor device 105 to fittherebetween. The support structure 136 may include a third side wall139 perpendicular to and extend between the side walls 138A and 138B.The support structure 136 may include three walls with one side open toslide the housing 110 between the side walls 138A and 138B. When thepatient is standing, for example, the third side wall 139 may preventthe coordinate locating device from sliding off of the housing 110 ofthe wearable sensor device 105. The housing 110 will have knowndimensions relative to the support structure 136 of the coordinatelocating device 135

The housing 110 may include a skin-contacting interface 115. In FIGS.2A-2C and 3 , the skin-contacting interface 115 is shown with dottedhatching. The skin-contacting interface 115 may include an adhesivecompatible with attachment to skin 15 (FIG. 4 ). The housing 110 isshown in vertical line hatching.

The system 100 may include an inertial measurement unit (IMU) 132. Thewearable sensor device 105 may be designed to be worn for one or moredays by patients experiencing musculoskeletal pain and/or neurologicalsymptoms. Similar to a Holter monitor, the wearable sensor device 105may continuously collect data about a patient's condition while they goabout their daily life. Instead of measuring heart activity throughsurface electrodes as is done with a Holter monitor, the wearable device105 may use the IMU 132 to measure the motion patterns of the region ofthe body to which it is adhered. These motion patterns may be used tomonitor musculoskeletal and/or neurological conditions and to measurethe impact that the disease is having on the everyday life of the wearer(i.e., patient).

The system 100 may include an ionizing radiation sensor 134. Theionizing radiation sensor 134 may be an X-ray sensitive element. Thedevice 105 may include a circuit board 118 with an IMU 132 electricallycoupled thereto. The device 105 may include circuit board 119 with anionizing radiation sensor 134 electrically coupled thereto. The circuitboard 118 and circuit board 119 are represented in diagonal hatching.While, the illustration illustrates two separate circuit boards, thecircuit boards may be circuit board portions of a single circuit boardin some scenarios.

The ionizing radiation sensor 134 may be an X-ray sensitive element. Itmay provide a timestamp associated with the time of the detection of theX-ray so that the sensor data could be “synchronized” with the X-ray(s).In other words, the instantiation in time at which an image is capturedfor a baseline coordinate reference is synchronized to the triggergenerated by the ionizing radiation sensor 134, as will be described inmore detail in relation to FIG. 5 .

The sensor device 105 via the skin-contacting interface 115 may beapplied to the back, such as the upper back, lower back or middle back,of a patient where it may remain for multiple days, actively recordingsensed data. By way of non-limiting example, the sensor device 105 isconfigured to monitor the motion of the torso—specifically the flexion,extension, lateral bending, and axial rotation allowed by the hips andlumbar spine. The relationship between the motion of the torso recordedby the wearable device 105 and the underlying boney anatomy may bedetermined with a secondary source of data (e.g., imaging machine 410).

The coordinate locating device 135 may be used to reveal a baselinerelationship between the motion of the torso and the positions of thebones and joints of the lumbo-pelvic-hip complex. The embodiments hereinmay be used to determine the distance between a motion sensor and ajoint. For example, the embodiments may place the wearable sensor device105 on a forearm, an elbow and/or shoulder. The wearable sensor device105 may be head-mounted, neck mounted or face mounted by the jaw. Thewearable sensor device 105 may be mounted on the cervical spine or otherportion of the spine. The wearable sensor device 105 may be mounted onthe leg, such as near a hip joint, a knee joint or ankle joint. Thecoordinate locating device 135 may then be used to reveal a baselinerelationship between the bones and joints.

The wearable sensor device 105 may be configured to provide asurgeon/radiologist with important context for interpreting an imagecaptured using an X-ray machine or CT scan machine. For example,standing X-rays are often used to determine the amount of angularcorrection required in a spine surgery. It is assumed that the postureof the individual in the X-ray is representative of that individual's“natural” posture. The wearable device 105 provides sensed data toconfirm the “natural” posture of the patient because it collectsmultiple days of posture data. During an initial image(s), baselineinformation is captured that can be later compared with the sensed dataduring a monitoring period.

One or more artificial intelligence (AI) algorithms, such as machinelearning algorithm (ML) or deep learning neural network (DL) may be usedto determine the patient' s natural standing posture by analyzing his orher standing posture during their daily life. Multiple algorithms may beused in succession or a staged approach to analysis. In one embodiment,the first stage of the analysis could be a series of ML or DL algorithmsto identify the time(s) within the data that the wearer was standing. Asecond stage could then analyze the data identified as standing andprovide an assessment of the most common postures. The most commonpostures could be analyzed together to generate a summary “natural”posture.

The wearable sensor device 105 may include other sensors (not shown)mounted to a circuit board. Other sensors may include, withoutlimitation, electrocardiogram (ECG) sensors, electromyography (EMG)sensors, barometers, thermometers or other thermal sensors, microphones,photoplethysmography (PPG) and/or the like. For example, the dataproduced by an ECG sensor is highly dependent on where the surfaceelectrodes are placed. If the surface electrodes are placed close to theheart and oriented to align with the mean electrical vector produced bythe depolarizations of the heart chambers, then the ECG waveform isoptimal. If the electrodes are moved away from the heart or misalignedwith the mean electrical vector, then the ECG waveform changes. It wouldbe beneficial to be able to predict a change in the ECG waveform byknowing the position of the ECG electrodes on the chest through themethod described in this patent. In some embodiments, the coordinatelocating device 135 may be configured to adapt to other sensors orelectrodes such as those for ECG sensors.

The system 100 may be configured to map the coordinate reference frameof one or more sensors embedded in the wearable sensor device 105 toanatomical landmarks. The anatomic landmarks may include bones, joints,and organs such as without limitation a heart. The device may mapaccelerometer coordinate reference frame, as well as a gyroscope andmagnetometer. The sensor coordinate reference frame(s) may be fixed.There is one coordinate reference frame per sensor. The sensor'scoordinate reference frame may cover all anatomic landmarks.

Referring now to FIG. 4 , the coordinate locating device 135 may includea distance locator 160 that defines or locates a distance calibrationphantom length D1 of pixels in an image. Assume that for the sake ofdiscussion, the view in FIG. 4 is a patient standing for a sagittal(longitudinal) X-ray. This can be applicable to a coronal plane CT scan,as well. A distance may be calculated to important radiographiclandmarks and fiducial marker components. The device 105 uses thedistance from the sensing center of the IMU 132 to the point of knowndistance (POKD) where a pixel/distance ratio is calculated. Then, theratio is applied to calculate the distance to a boney anatomy landmarkof interest. The POKD in the illustration corresponds to the distancelocator 160. The distance locator 160 may be used interchangeably withthe terms “third fiducial marker component,” “point of known distance”and “fiducial marker.”

Phantom is an accepted term for an item that is used as a reference inradiography. The most common use of a “phantom” can be used to estimatebone density in radiography. The phantom has different regions of knowndensity/radiopacity and it is placed next to the bone being studied. Thegreyscale color of the bone is then compared to the greyscale color ofthe regions of the phantom. The region of the phantom that matches thecolor of the bone tells you the approximate density of the bone.

The position and orientation of a patient's anatomy structures 405 maybe determined using a vision system employing ionizing radiation tocapture both the radiopaque markers and the boney anatomy structures 405correlated with IMU data from an IMU affixed to the patient's skin 15 atthe instantiation of imaging. The location of the anatomy landmark 407may be located in the image. The location of the anatomy landmark 407may be registered by determining distances D2 and D3 relative to thespine's axis SA where boney anatomy structures rotate or bend relativeto the spine's axis SA. The distance D2 is orthogonal to the spine'saxis SA and extends from the point of sensing origin to the spine's axisSA.

As shown, in FIG. 4 , the fiducial markers 154 have shifted undergravity. When the system 100 is imaged at different angles, the fiducialmarkers 154 of the gravity indicator (i.e., second fiducial markercomponent 150) are also captured. In the image, the fiducial markers 154of the gravity indicator (i.e., second fiducial marker component 150)may be in-line with the fiducial marker of the distance locator 160.

FIG. 5 is a block diagram of example electrical components of thewearable sensor device 505 (i.e., wearable sensor device 105). Thewearable sensor device 505 may include a processor 520 and memory 530.The wearable sensor device 505 may include a clock (CLK) 522electrically coupled to or integrated in the processor 520. The clocksignal from the clock 522 may be used in generating a timestamp 524. Thewearable sensor device 505 may include a battery 535 for powering theelectrical components. The wearable sensor device 505 may include an IMU532 having an accelerometer 533 and a gyroscope 537, by way ofnon-limiting example, or other motion sensing devices. The IMU 532 mayinclude a magnetometer 539 represented in a dashed box to denote that itis optional. The IMU 532 (i.e., IMU 132) may be configured to detect six(6) to nine (9) degrees of freedom or human anatomy axes of motion. Thedevice 505 may include a gravity indicator 550 (i.e., second fiducialmarker component 150).

In operation, the processor 520 stores the IMU data with the timestamp524 generated in response to the trigger from the ionization radiationsensor 534.

The wearable sensor device 505 may include a communication unit 540configured to generate an electronic communication signal including theIMU data and a timestamp 524. The timestamp 524 generated during thebaseline collection of sensed data is generated in response to theionizing radiation sensor 534 (i.e., ionizing radiation sensor 534)detecting ionizing radiation (OR) from a source of ionizing radiation,such as an imaging machine 410. The stored timestamp and IMU data isalso generated and collected during a monitoring phase and communicatedvia the communication unit 540 to a remote computing system 576 or alocal computing system 570 via the Internet, Intranet or othercommunication network 565. The IMU data may include (X, Y, Z) Cartesiancoordinates and (yaw, pitch, roll) data. The IMU data may includeinformation associated with gravity.

The remote computing system 576 may be a website or cloud computingsystem 572 including a cloud database 580. The cloud database 580 storesthe data including the timestamp 582, the IMU data 584 and the IRS data586. The IRS data 586 synchronizes the IMU data and timestamp datacollected for each instantiation of imaging at which ionizing radiationis generated. The remote computing system 576 may include an imageprocessing system (IPS) 573 with machine learning (ML) algorithms 574for performing one or more blocks of the methods described herein. Thelocal computing system 570 may also include an IPS and ML algorithms forperforming one or more blocks of the methods described herein.

FIG. 6A is a diagram of axes of the human anatomy 600A. FIG. 6B is adiagram of the planes of the human anatomy 600B. The sensor device 105may be constructed and arranged as a six (6) or nine (9) axis inertialmeasurement unit (IMU). For example, the six degrees of freedom include(X, Y, Z) Cartesian coordinates corresponding to an X-axis, Y-axis andZ-axis. The six degrees of freedom may include information associatedwith the sagittal plane, frontal plane and traverse planes. Informationassociated with the axes may include the pitch, yaw and roll data.

The movement of the patient may include movement associated with afrontal coronal plane, a sagittal plane and/or a traverse plane.

The blocks of the methods described herein may be performed in the ordershown or a different order. The one or more of the blocks may beperformed contemporaneously. Method blocks may be omitted and/or added.

FIG. 7 is a flowchart of an embodiment of a method 700 for generating amap of a sensor's baseline coordinate reference frame. The method 700will be described in combination with the electrical components of thesensor device 505 (i.e., sensor device 105). In operation, the method700 may include, at block 702, affixing or attaching the wearable sensordevice 105 on and to the skin 15 of a patient at a location adjacent tothe thoracolumbar or trunk, via the skin-contacting interface 115. Thethoracolumbar spine that may include the vertebrae T1-T12 and theintervertebral discs therebetween. The embodiments have application tothe cervical section of the spine and the lumbar section of the spine.Anatomic regions of interest may include lumbar spine, pelvis, hipjoint, and others. Therefore, the wearable sensor device 105 may beattached to any of these regions of interest. The method 700 may berepeated if multiple sensor device 105 are attached. Furthermore, priorto capturing the data for the baseline coordinate reference, the sensordevice 105 may have already been affixed or attached.

The method 700 may include, at block 704, connecting the coordinatelocating device 135 (FIG. 1 ) with the different fiducial markercomponents 140, 160 and 150 to the housing 110 of the sensor device 105(i.e., sensor device 505).

The method 700 may include, at block 705, recording of the sensed datafrom the IMU 532 of the sensor device 105, once the sensor device 105 isactivated. The IMU data from the IMU 532 may include accelerometer datafrom accelerometer 533, gyroscope data from gyroscope 537 and, in someembodiments, magnetometer data from magnetometer 539. The recording maybegin prior to block 704 and may be a function of when the sensor device105 is activated.

To generate the baseline coordinate reference, imaging should commence.The method 700 may include, at block 706, radiating ionizing radiationfrom an imaging machine 410 (FIG. 4 ). The method 700 may include, atblock 708, detecting the ionizing radiation by the ionization radiationsensor 534 of the sensor device 505. The method 700 may include, atblock 710, generating a baseline timestamp in response to detecting theionizing radiation from the imaging machine 410. The method 700 mayinclude, at block 712, synchronizing the IMU data from the IMU 132 withthe baseline timestamp. The timestamp represents, in general, theinstant that the radiograph was taken. The processor 520 is configuredto synchronize the instantiation of imaging by the imaging machine(i.e., imaging machine 410) with the output of the IMU 532 of thewearable device 505. By way of non-limiting example, the synchronizationis between an ionizing radiation sensor 534 on the wearable device 505and the IMU 532. The ionizing radiation sensor 534 would sense the X-rayand alert the processor 520. The processor 520 would record the timeusing an internal clock 522 common to the IMU 532 for synchronizationwith the timing of the X-ray.

Synchronization between the ionizing radiation sensor 534 and the IMU532 of the wearable device 505 may use signals received viacommunication unit 540. For example, the imaging machine 410 or anotherdevice could send a signal to the wearable device 505 corresponding tothe moment of the radiation of the ionizing radiation (OR) from animaging machine. By way of non-limiting example, the IMU data mayinclude (X, Y, Z) Cartesian coordinates and (yaw, pitch, roll) data. TheIMU data may include information associated with gravity.

The method 700 may include, at block 714, capturing by the imagingmachine 410 images, in response to radiating the patient with theionizing radiation. The images can be a single image in which thepatient is still, or a series of images in which the patient moves theirtrunk using their boney anatomy structures 405 (FIG. 4 ). The method 700may include, at block 716, a determination whether imaging is complete.If the determination is “NO,” the method loops back to block 706 wherecapturing of images continues. If the determination is “YES,” the method700 may include, at block 718, mapping a sensor's baseline coordinatereference frame based on the synchronized IMU data and the capturedimages. In the captured images, the different fiducial marker(s) of thecoordinate locating device 135 are captured along with the IMU 532 andunderlying boney anatomy structure 405 to identify a landmark 407. Eachmarker is registered to a set of pixels in the captured imagecorresponding to the marker's pixel location in the image. The mappingat block 718 may be performed by a remote computing system 576 or alocal computing system 570. A different baseline coordinate referenceframe may be generated for a different landmark identified on theunderlying boney anatomy structure 405.

The coordinate locating device 135 may include markers 141, 142 and 143.When imaging is performed, the coordinate locating device 135 is imagedfrom different angles or pose. A 3D representation of the fiducialmarkers 141, 142 and 143 may be used to develop a baseline of the sensordata in a 2D representation of the image. The radiopaque markers 141,142 and 143 allows the device's position and orientation within an imageto be matched to a pixel coordinate system of the imaging machine 410.The fiducial marker 160 of the position locator provides a calibrationlength in the image. The calibration length is associated with pixels inthe image that correspond to the length.

The coordinate locating device 135 may further include radiopaquegravity direction markers 154 that may be imaged simultaneously whenfiducial markers 141, 142 and 143 and fiducial marker 160 are imaged.Each image from the imaging machine 410 causes the ionization radiationsensor 534 to trigger a timestamp for synchronizing the IMU data readingwith the instantiation of imaging. The IMU data may include datarepresentative of the gravity reading of the IMU 532 that is paired withthe baseline timestamp. Thus, the image processing analysis via the IPS573 is configured to compare the gravity reading of the IMU 532 with thedirection of gravity vector imaged processed gravity reading based onthe position of fiducial markers 154 to compensate for any offsets inthe IMU gravity. The processor 520 configured to synchronize an internalclock 522 used by the IMU with the baseline timestamp. The clock 522being adjusted based on the logged time of the baseline timestamp. TheIMU data being adjusted based on a baseline anatomical position loggedat the time of the baseline timestamp. The sample rate of the IMU 532may be constant, in some embodiments.

Once the mapping is complete, one or more of the sensors' baselinecoordinate reference frames have been generated and the method 700 ends,at block 720. By way of non-limiting example, different landmarks may beused to generate different baseline coordinate reference frames.

FIG. 8 is a flowchart of an embodiment of a method for generating a mapof a motion sensor coordinate reference frame. The method 800 mayinclude, at block 808, recording of the sensed data from the IMU 532 ofthe sensor device 505. The recording of data in the method 800 is themonitored data after the baseline coordinate reference frame has beengenerated. The recording may take place over several days, for example

The IMU data from the IMU 532 may include accelerometer data fromaccelerometer 533, gyroscope data from gyroscope 537 and, in someembodiments, magnetometer data from magnetometer 539.

The method 800 may include, at block 810, generating a timestamp usingthe internal clock 522. The method 800 may include, at block 812,synchronizing the IMU data from the IMU 532 with the timestamp of theclock 522. By way of non-limiting example, the IMU data may include (X,Y, Z) Cartesian coordinates and (yaw, pitch, roll) data. The IMU datamay include information associated with gravity. The method 800 mayinclude, at block 816, mapping the sensor's coordinate reference framebased on the motion sensed data. The method 800 may include, at block818, adjusting the map motion sensor coordinate reference frameaccording to an offset with the baseline coordinate reference frame.

FIG. 9A is a flowchart of an embodiment of a method 900 for analyzingthe map of the sensor's baseline coordinate reference frame. FIG. 9B isa diagram of an example sagittal plane offset. The method 900 mayinclude, at block 902, identifying different fiducial marker componentsof the coordinate locating device 135 and determine orientation of thedifferent fiducial marker components with respect to the X-ray plane orimaging machine's plane, as will be described in more detail in relationto FIGS. 10-11 .

Embodiments of the imaging devices herein may relate generally, forexample, to systems, devices, and methods for image guided medicalprocedures. More particularly, embodiments of the imaging device mayrelate to surgical navigation systems 950, devices, and methods withanatomical tracking for performing image guided medical procedures. Forexample, such surgical navigation systems 950, devices, and methods maybe those used in the FluoroNav™ system that utilizes the StealthStation®Treatment Guidance Platform, both of which are available from MedtronicSofamor Danek, Inc. The StealthStation® Treatment Guidance Platform, andin particular the StealthStation® Navigation System, is described inpart in the “StealthStation® S7® Treatment Guidance System Manual”published by Medtronic, Inc. in 2012, the “StealthStation™ S8 SpinalNavigation Solution” brochure published by Medtronic, Inc. in 2019, andin “The Clinical and Economic Benefits of Using StealthStation®Navigation and O-arm® Imaging Systems for Spine Surgery” brochurepublished by Medtronic, Inc. in 2014. Embodiments of the surgicalnavigation systems 950, devices, and methods with anatomical tracking,as shown in FIG. 9B.

The imaging machine 410 may be part of a StealthStation® NavigationalSystem such as a StealStation® S7® or StealStation® S8® by MedtronicInc. The navigation system 950 may include a display 960. The navigationsystem 950 being configured to create a translation map between all or asubset of points in the patient image and corresponding points on thepatient anatomy. The imaging machine 410 is configured to provideregistration and image acquisition for navigation. The imaging machinemay provide optical systems to determine the position of the (optical)markers. The imaging machine may include an optical localizer 970. Theoptical localizer 970 may include a camera with a field of view thatdefines an optical navigation field by detecting optical markers anddetermines their spatial positions using triangulation in a displayedimage. The optical localizer 970 may include a laser positioning systemassociated with the camera.

While, the embodiments describe passive optical radiopaque fiducialmarkers, one or more of the fiducial markers may include a lightemitting diode (LED). In such an embodiments, the coordinate locatingdevice would be equipped with a battery or power source (not shown).

The imaging machine 410 may be an O-arm® Imaging System, by MedtronicInc., configured to provide high-resolution real-time 2D fluoroscopicand 3D imaging with multiplanar view.

In one or more cases, the navigation system 950 may be configured toregister the acquired image data to one or more coordinate systems. Inone or more cases, one or more smartglasses (not shown) are configuredto display one or more superimposed images over a portion of thepatient. In one or more cases, the one or more superimposed images maybe related to the acquired image data. In one or more cases, the one ormore smartglasses are further configured to align the one or moresuperimposed images to correspond with a position of the at least oneobject.

In some embodiments, the imaging device may include those disclosed inU.S. Pat. Nos. 7,188,998; 7,108,421; 7,106,825; 7,001,045; and6,940,941; all of which are incorporated herein in their entirety byreference, or any appropriate portions thereof.

The method 900 may include, at block 904, identifying anatomicallandmarks 407 (FIG. 4 ) of interest and calculate their (i.e.,landmarks) orientation with respect to the X-ray plane or imagingmachine's plane. Assume, that the spine's axis (SA) is normal ororthogonal to the X-ray plane or imaging machine's plane. By way ofnon-limited example, calculate the angle (α) between the mid-sagittalplane and the X-ray plane using existing methods.

There are three sets of planes, X-ray plane, anatomic planes and sensorplanes. For example, for an X-ray plane, a single plane is fixedrelative to the imaging machine. The anatomic planes may include threeorthogonal planes (sagittal, coronal, and axial) that are fixed withrespect to the person. The sensor planes may include three planes (X-Y,Y-Z, and X-Z) that are fixed relative to the sensor of the sensor device105. The anatomic planes may be misaligned with the X-ray plane. Theamount of misalignment (i.e., out-of-plane angle) would be calculatedusing the methods described herein, for example, as related to FIGS.9A-9B, 10, 11 and 12 .

For example, in block 906, the sensor planes may be misaligned with theanatomic planes. The amount of misalignment would be determined by i.)identify misalignment between the midsagittal plane and the X-ray planeusing the existing methods; ii.) identify the misalignment between thesensor plane and the X-ray plane by using the locations of fiducialmarkers 141, 142, and 143; and iii.) subtract the misalignmentcalculated in (i.) from the misalignment calculated in (ii.).

The method 900 may include, at block 906, calculating the angle (β)being the difference between the plane defined by the sensorsforward/vertical axes and the mid-sagittal plane in the direction ofARROW 2. By way of non-limiting example, all of the IMU data may berotated by this angle (β) so that the sensor's baseline coordinatereference frame is aligned to the mid-sagittal plane.

The method 900 may include, at block 908, calculating the relationshipbetween trunk motion patterns and pain generators identified on theradiograph such as using the X-ray machine or CT scan machine.

The method 900 may include, at block 910, calculating the anatomiccenter of rotation for the trunk based on the rotations recorded by theIMU 132 and the boney landmarks 407 visible in the captured image by theimaging machine.

The coordinate locating device 135 with radiopaque fiducial markers areaffixed to the sensor device 104 while the sensor device 105 is beingworn by an individual. In some scenarios, the patient will be standingupright. Then, the spine of the patient and the device 105 are imagedwith ionizing radiation in one or more planes. Multiple images may becaptured in succession to show the fiducial markers for calculating thedistance between the markers and the sensing axes of the baselinecoordinate reference frame. The distance between the baseline coordinatereference frame and relevant boney landmarks can then be determined.

FIG. 10 is a flowchart of an embodiment of a method 1000 for identifyingthe different fiducial marker components of the coordinate locatingdevice 135 and their orientation relative to the X-ray plane to locatethe point of sensing origin of the inertial measurement unit (IMU). FIG.10 will be described in relation to FIG. 9B. The method 1000 correspondsto the functions to be performed at block 902 of the method 900.

The method 1000 may include identifying fiducial markers 141, 142, and143 for 3D space representation in a 2D image, identifying the distancelocator fiducial marker 160 and notch 164 in the image; and identify theat least one gravity direction fiducial marker 154 in the image. Theimage may be processed using image processing analysis via the IPS 573to perform feature extraction using machine learning algorithms and/ordeep learning algorithms including supervised and unsupervised learningalgorithms. The feature extraction and classification algorithms such asfor identifying landmarks of the boney structures may be used.

The method 1000 may include determining the orientation of the fiducialmarker components with respect to the X-ray plane or the imagingmachine's plane (FIG. 9B), at block 1012. At block 1012, the method 1000may determine the position of marker 141 at block 1014A, marker 142 atblock 1014B, and marker 143, at block 1014C. There are known algorithmsto determine the out-of-plane rotation of 3D space fiducial markersarranged in a non-collinear orientation.

The method 1000 may include, at block 1016, identifying a distancecalibration phantom via the distance locator fiducial marker 160, aswill be described in more detail in relation to FIG. 12 . The method1000, may include locating the point of sensing origin of the IMU 532.The point of sensing origin is registered to set the coordinates of thepoint of sensing origin to X=0, Y=0 and Z=0 denoted as (0, 0, 0) insensor's coordinate reference frame and would be calculated based on aknown distance between the distance locator (i.e., the distance locatorfiducial marker 160) and the sensor package, such as the chip or circuitof the IMU 132. The image processing analysis via the IPS 573 woulddetermine a pixel length metric of a fixed length between the fiducialmarker 160 and the notch 164. The image processing analysis via the IPS573 calibrates the pixel length D1 to extrapolate the distance D2 (FIG.4 ) such as to the spine's axis (SA).

The chamber 152 containing the gravity direction radiopaque fiducialmarkers 154 gives an indication of the direction of the gravity vector.This information can be used in two ways. First, the gravity vector maybe used, for example, to inform radiographic measures, such as the C7plumb line, that require knowledge of the gravity vector. Traditionally,radiologists/spine specialists approximate the gravity vector whendrawing measurements that use it. The radiopaque fiducial markers 154may be used as a tool to identify the gravity vector. Second, thegravity vector may ensure that the gravity vector measured by the IMUdoes not deviate significantly from the gravity line that will be usedin radiographic measurements of the spine. The gravity vector derivedfrom the image of the chamber 152 containing gravity directionradiopaque fiducial markers 154 may not necessarily be used to calibratethe accelerometer of the IMU. However, the gravity direction radiopaquefiducial markers 154 may, for example, be used as an in vivo measure ofaccuracy to determine if the accelerometer is not suitable for use.Through these two uses, the gravity direction radiopaque fiducialmarkers 154 serves to strengthen the connection between the anatomy andthe sensor data. Both the IMU data and relevant radiographic parametersare calibrated according to a common gravity indicator.

FIG. 11 is a flowchart of an embodiment of a method 1100 for determiningan orientation of the set of non-collinear fiducial markers relative tothe X-ray plane to generate a 3D space pixel metric for the sensor'sbaseline coordinate reference frame. The method 1100 corresponds to thefunctions to be carried out at block 1012 of FIG. 10 . The method 1100may include, at block 1110, automatically determining the out-of-planeangle (i.e., angle β) by determining the distance between the threeorientation fiducial markers 141, 142 and 143 within the X-ray plane.

The method 1100 may include, at block 1112, identifying regions ofinterest in images using machine learning (ML). An algorithm would beselected based on its ability to differentiate the radiopaque fiducialmarkers 141, 142, 143 from other radiopaque objects or fiducial markerswithin the same image. The method 1100 may include determining whereeach fiducial marker of the non-collinear marker set is recognized, atblock 1114. If the determination is “NO,” the method loops back to block1112 until all the fiducial markers of the non-collinear set arerecognized for the 3D space pixel metric. If the determination is “YES,”the method, at block 1116, may include calculating the relativedistances between the centers of the three markers of the non-collinearset. The method 1100 may include, at block 1118, comparing thesedistances to the known distances between the markers of thenon-collinear set to determine the out-of-plane angle β.

FIG. 12 is a flowchart of an embodiment of a method 1200 for identifyingthe distance calibration phantom pixel metric for the sensor's baselinecoordinate reference frame. The method 1200 may correspond to thefunctions to be carried out by block 1016 of FIG. 10 .

The method 1200 may include, at block 1210, once the out-of-plane angleβ is determined, identify the distance calibration phantom (i.e., thedistance locator fiducial marker 160). The method 1200 may include, atblock 1212, calculating the distance calibration phantom length inpixels to develop a calibration pixel length metric. The method 1200 mayinclude, at block 1214, comparing the distance phantom length to theknown length of the feature, as well as the out-of-plane angle β. Themethod 1200 may include, at block 1216, calculating a pixel/distanceratio. This ratio can be used to calculate a distance between thesensor's point of sensing origin in Cartesian coordinate referenceframe) and various parts of the spine in the image.

The thoracolumbar spine may include the vertebrae T1-T12 and theintervertebral discs therebetween.

Relevant anatomic landmarks include the posterior superior corner of thefirst sacral vertebra (S1), the C7 plumb line (i.e., a vertical lineparallel to gravity drawn from the center of the seventh vertebra of thecervical spine to the ground), the center of the femoral head, themidpoint of the sacral plate, and other anatomical honey structures.

The images can be planar or CT. They can be single-shot images in whichthe individual is still, or a series of shots in which the individualmoves their trunk. The distance between known points on the coordinatelocating device 135 is used to determine the pixel/distance ratio. Then,the distance between the sensor's point of sensing origin in Cartesiancoordinate reference frame and various parts of the spine can becalculated. The sensor device 105 in the primary embodiment would be a6- or 9-axis inertial measurement unit. Relevant anatomic landmarksinclude the posterior superior corner of S1, the C7 plumb line, thecenter of the femoral head, the midpoint of the sacral plate, and manymore.

The system 100 is configured to bridge the gap in surgeon's mindsbetween familiar data (imaging studies of the spine) and the unfamiliardata captured through the wearable device 105 (human motion data). Inthe current standard practice for the treatment of spinal diseases, thesurgeon consults imaging studies of the spine to determine the amount ofsurgical correction required by the patient. It is widely recognizedthat the posture adopted by an individual during imaging studies may notbe fully representative of that individual's true comfortable posture.The human motion data captured continuously for multiple days by thewearable device can shed light on the individual's true comfortableposture.

While the embodiments provide the radiopaque fiducial markers on acoordinate locating device, the radiopaque fiducial markers may be builtinto the wearable sensor device 105.

It should be understood that various aspects disclosed herein may becombined in different combinations than the combinations specificallypresented in the description and accompanying drawings. It should alsobe understood that, depending on the example, certain acts or events ofany of the processes or methods described herein may be performed in adifferent sequence, may be added, merged, or left out altogether (e.g.,all described acts or events may not be necessary to carry out thetechniques). In addition, while certain aspects of this disclosure aredescribed as being performed by a single module or unit for purposes ofclarity, it should be understood that the techniques of this disclosuremay be performed by a combination of units or modules associated with,for example, a medical device.

In one or more examples, the described methods or one or more blocks ofthe methods may be implemented in hardware, software, firmware, or anycombination thereof. If implemented in software, the functions may bestored as one or more instructions or code on a computer-readable mediumand executed by a hardware-based processing unit. Computer-readablemedia may include non-transitory computer-readable media, whichcorresponds to a tangible medium such as data storage media (e.g., RAM,ROM, EEPROM, flash memory, or any other medium that can be used to storedesired program code in the form of instructions or data structures andthat can be accessed by a computer).

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor” as used herein may refer toany of the foregoing structure or any other physical structure suitablefor implementation of the described techniques. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

FIG. 13 depicts an example of internal hardware that may be included inany of the electronic components of an electronic device as described inthis disclosure such as, for example, an on-premises electronic device,an associate electronic device, a remote electronic device, remotecomputing system, local computing system and/or any other integratedsystem and/or hardware that may be used to contain or implement programinstructions. The wearable sensor device 105 is an electronic device.

A bus 1300 serves as the main information highway interconnecting theother illustrated components of the hardware. CPU 1305 is the centralprocessing unit of the system, performing calculations and logicoperations required to execute a program. CPU 1305, alone or inconjunction with one or more of the other elements disclosed in FIG. 13, is an example of a processor as such term is used within thisdisclosure. Read only memory (ROM) and random access memory (RAM)constitute examples of tangible and non-transitory computer-readablestorage media 1320, memory devices or data stores as such terms are usedwithin this disclosure. The memory device may store an operating system(OS) of the server or for the platform of the electronic device.

Program instructions, software or interactive modules for providing theinterface and performing any querying or analysis associated with one ormore data sets may be stored in the computer-readable storage media1320. Optionally, the program instructions may be stored on a tangible,non-transitory computer-readable medium such as a compact disk, adigital disk, flash memory, a memory card, a universal serial bus (USB)drive, an optical disc storage medium and/or other recording medium.

An optional display interface 1330 may permit information from the bus1300 to be displayed on the display 1335 in audio, visual, graphic oralphanumeric format. Communication with external devices may occur usingvarious communication devices or ports 1340. A communication devices orports 1340 may be attached to a communications network, such as theInternet or an intranet. In various embodiments, communication withexternal devices may occur via one or more short range communicationprotocols. The communication devices or ports 1340 may includecommunication devices for wired or wireless communications.

The hardware may also include an interface 1345, such as graphical userinterface (GUI) that allows for receipt of data from input devices suchas a keyboard or other input device 1350 such as a mouse, a joystick, atouch screen, a remote control, a pointing device, a video input deviceand/or an audio input device. The interface 1345 may include a sensor,such as without limitations, in touch screens. The hardware may includeimaging device 1360 configured to capture images using ionizingradiation. The imaging device 1360 is an ionizing radiation machine.

Common forms of computer-readable media include, for example, a floppydisk, a flexible disk, a hard disk, a magnetic tape, or any othermagnetic medium, a compact disk ROM (CD-ROM), a digital video disk (DVD)or any other optical medium, punch cards, paper tape, or any otherphysical medium with patterns of holes, a RAM, a programmable ROM(PROM), an erasable PROM (EPROM), a FLASH-EPROM, or any other memorychip or cartridge from which a computer can read. The termnon-transitory computer-readable storage medium is used herein to referto any medium that participates in providing information to processor,except for carrier waves and other signals.

Computer program code for carrying out operations described above may bewritten in a variety of programming languages, including but not limitedto a high-level programming language, such as without limitation, C orC++, Python, and Java for development convenience. In addition, computerprogram code for carrying out operations of embodiments described hereinmay also be written in other programming languages, such as, but notlimited to, interpreted languages. The program code may include hardwaredescription language (HDL) or very high speed integrated circuit (VHSIC)hardware description language, such as for firmware programming. Somemodules or routines may be written in assembly language or evenmicro-code to enhance performance and/or memory usage. It will befurther appreciated that the functionality of any or all of the programmodules may also be implemented using discrete hardware components, oneor more application specific integrated circuits (ASICs), or aprogrammed Digital Signal Processor (DSP) or microcontroller. A code inwhich a program of the embodiments is described can be included as afirmware in a RAM, a ROM and a flash memory. Otherwise, the code can bestored in a non-transitory, tangible computer-readable storage mediumsuch as a magnetic tape, a flexible disc, a hard disc, a compact disc, aphoto-magnetic disc, a digital versatile disc (DVD) or the like.

In this document, “electronic communication” refers to the transmissionof data via one or more signals between two or more electronic devices,whether through a wired or wireless network, and whether directly orindirectly via one or more intermediary devices. Devices are“communicatively connected” if the devices are able to send and/orreceive data via electronic communication.

The features and functions described above, as well as alternatives, maybe combined into many other different systems or applications. Variousalternatives, modifications, variations or improvements may be made bythose skilled in the art, each of which is also intended to beencompassed by the disclosed embodiments.

What is claimed is:
 1. A system, comprising: a wearable sensor devicecomprising: a housing; and a skin-contacting interface configured toform a continuous boundary between the wearer and the housing; thehousing containing an inertial measurement unit (IMU) and an x-raysensor configured to, in response to sensing x-rays radiating from animaging device, trigger a processor to generate a baseline timestamp andstore the baseline timestamp and data from the inertial measurement unitto synchronize IMU data with an image captured by the imaging device;and a coordinate locating device configured to be removably connectableto the wearable sensor device wherein the coordinate locating devicecomprises a plurality of different fiducial marker components beingradiopaque to the x-rays of the imaging device.
 2. The system accordingto claim 1, wherein the coordinate locating device comprises: a supportstructure removably connectable to the wearable sensor device, thesupport structure comprising a planar surface; and the plurality ofdifferent fiducial marker components includes: a set of fiducial markersconnected to the planar surface in a non-collinear configurationrelative to each other to define a three-dimensional (3D) space ofpixels in the captured image; and a distance calibration fiducial markerconnected to the planar surface and being configured to define adistance calibration length of pixels in the image, the distancecalibration fiducial marker being perpendicular to the planar surfaceand defines the calibration length of the pixels to locate a point oforigin of motion sensing by the IMU.
 3. The system according to claim 2,wherein the different fiducial marker components further comprise: atleast one gravity direction fiducial marker that moves in response to aforce of gravity to locate a direction of gravity, at an instantiationof imaging at which the image is captured.
 4. The system according toclaim 3, wherein the support structure further comprises a chambermounted to the planar surface wherein the at least one gravity directionfiducial marker comprises a plurality of loose radiopaque ballsconfigured to move within the chamber in response to the force ofgravity.
 5. The system according to claim 3, wherein the supportstructure further comprising a chamber mounted to the planar surface anda fluid stored in the chamber wherein the at least one gravity directionfiducial marker comprises a radiopaque element configured to move withinthe chamber in response to the force of gravity.
 6. The system accordingto claim 2, wherein the distance calibration fiducial marker comprises:a stem having a stem length, the stem includes a first end connected tothe planar surface; a radiopaque marker connected to a second end of thestem, the radiopaque marker having at least one dimension; and a notchformed in the stem wherein the distance calibration length is measuredfrom a predetermined location associated with the notch to apredetermined location of the radiopaque marker.
 7. The system accordingto claim 2, wherein the IMU comprises an accelerometer and a gyroscopeto measure an orientation in real-time of an anatomical position of abody part immediately adjacent to the wearable sensor device.
 8. Thesystem according to claim 7, wherein the orientation of the anatomicalposition of the body part is determined based on six degrees of freedomincluding X, Y, Z coordinates on a Cartesian coordinate system andpitch, yaw, and roll.
 9. The system according to claim 8, wherein theIMU data comprises the orientation and gravity direction data.
 10. Thesystem according to claim 9, wherein: the plurality of differentfiducial marker components further comprises: at least one gravitydirection fiducial marker that moves in response to a force of gravityto locate a direction of gravity vector at an instantiation of imagingat which the image is captured.
 11. A method, comprising: sensing, by awearable sensor device including an inertial measurement unit (IMU),inertial measurement data associated with an anatomical position of aboney anatomical structure, the wearable sensor device comprising: ahousing containing the IMU and an x-ray sensor, and a skin-contactinginterface forming a continuous between the wearer and the housing;receiving, by the wearable sensor device, a coordinate locating deviceincluding a plurality of different fiducial marker components beingradiopaque to x-rays of an imaging device; sensing, by the x-ray sensorof the wearable sensor device, the x-rays radiating from the imagingdevice to trigger a processor to generate a baseline timestamp and storethe baseline timestamp and data from the inertial measurement unit tosynchronize the inertial measurement data with an image of the boneyanatomical structure captured by the imaging device; and imaging, usingthe imaging device, the coordinate locating device connected to thewearable sensor device.
 12. The method according to claim 11, wherein:the imaging of the coordinate locating device includes: imaging a set offiducial markers, of the plurality of different fiducial markercomponents, connected to a planar surface in a non-collinearconfiguration relative to each other to define a three-dimensional (3D)space of pixels in the image; and imaging a distance calibrationfiducial marker, of the plurality of different fiducial markercomponents, connected to the planar surface and being configured todefine a distance calibration length of pixels in the image, thedistance calibration fiducial marker being perpendicular to the planarsurface and defining the calibration length of the pixels to locate apoint of origin of motion sensing by the IMU.
 13. The method accordingto claim 12, wherein: the imaging of the coordinate locating devicefurther comprises: imaging at least one gravity direction fiducialmarker, of the plurality of different fiducial marker components, thatmoves in response to a force of gravity to locate a direction of gravityvector at an instantiation of imaging at which the image is captured.14. The method according to claim 11, wherein the inertial measurementdata comprises a measure of an orientation in real-time of theanatomical position of a body part immediately adjacent to the wearablesensor device and the orientation of the anatomical position of the bodypart is determined based on six degrees of freedom including X, Y, Zcoordinates on a Cartesian coordinate system and pitch, yaw, and roll.